Mirroring the Team Foundation Data-Tier Server

You can synchronize your Team Foundation data-tier server with a copy on another server. This process is referred to as database mirroring. The Team Foundation data-tier server becomes the principal server, and the server that contains the copy becomes the mirroring server. By mirroring your Team Foundation data-tier server, you can manually switch over from the principal Team Foundation data-tier server to the mirroring server.

Advantages of Mirroring the Team Foundation Data-Tier Server

Mirroring the Team Foundation data-tier server has several advantages. It enables you to take the principal Team Foundation data-tier server offline for updates, maintenance, or repair with minimal impact on your Team Foundation Server users. It also enables a quick recovery mechanism if the principal Team Foundation data-tier server becomes unavailable. Mirroring the Team Foundation data-tier server complements other Team Foundation availability and recovery strategies, such as setting up a standby application-tier server, and supplements backup and restore strategies. However, you should not consider Team Foundation data-tier server mirroring a replacement strategy for regular backups of Team Foundation data. For more information, see Ensuring Team Foundation Server Availability and Backing Up and Restoring Team Foundation Server Data.

How Database Mirroring Works

Database mirroring keeps the Team Foundation databases on the principal Team Foundation data-tier server synchronized with copies on the mirroring server. Only the principal Team Foundation data-tier server's databases are available for use by Team Foundation Server. Communication between the principal and mirroring servers can be either asynchronous or synchronous.

The mirroring server's databases can become the principal databases in a process that is referred to as role switching. Role switching involves transferring the principal role to the mirror server. In role switching, the mirror server acts as the failover partner for the principal server. When a role switch occurs, the mirror server takes over the principal role and brings its copy of the database online as the new principal database. The former principal server, if available, assumes the mirror role, and its database becomes the new mirror database. Potentially, the roles can switch back and forth repeatedly. For more information about role switching, see the documentation for Microsoft SQL Server 2005 on the Microsoft Web site (http://go.microsoft.com/fwlink/?LinkId=77987). For Team Foundation Server, you must manually fail over the databases in order to switch the roles between the principal Team Foundation data-tier server and the mirroring Team Foundation data-tier server. Automatic fail-over is not supported.